The invention relates to a sintered transformer or inductor core of NiZn ferrite material. The invention also relates to an inductor and a transformer which are provided with such an inductor respectively transformer core. By means of a transformer the voltage and/or the current intensity of a current source can be converted to another desired voltage and/or current intensity.
A transformer core of the type mentioned in the opening paragraph is known per se. For example, in Philips Data Handbook MA-01, 1993, pp. 131 and 132, a NiZn core is disclosed which is referred to as 4F1. The material composition of the core described in said handbook corresponds to the formula Ni.sub.0.49 Zn.sub.0.49 Co.sub.0.02 Fe.sub.1.90 O.sub.3.85. This transformer core is intended for use, in particular, in a so-called "power-transformer". This type of transformer can suitably be operated at frequencies in the MHz range and at relatively high induction values of 5 mT or higher.
The drawback of the known transformer or inductor core is that it exhibits relatively high overall losses per volume unit (P) if it is used in a "power-transformer". Said losses cause the transformer to heat up. In particular, if the transformer is used at frequencies of from 2 MHz it heats up to relatively high temperatures. For example, as shown in FIG. 7 on page 132, at 20.degree. C. an overall loss per volume unit of 190 mW/cm.sup.3 is measured on these cores at an induction of 10 mT and a frequency of 3 MHz.